Stuart Lindsay talks with
ScienceWatch.com and answers a few questions about
this month's Emerging Research Front Paper in the field of
Article: A bond-fluctuation mechanism for
stochastic switching in wired molecules
Authors: Ramachandran, GK;Hopson, TJ;Rawlett, AM;Nagahara,
Journal: SCIENCE, 300 (5624): 1413-1416 MAY 30 2003
Addresses: Arizona State Univ, Dept Phys & Astron,
Tempe, AZ 85287 USA.
Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287
Arizona State Univ, Azbiodesign Inst, Tempe, AZ 85287
Motorola Labs, Phys Sci Res Labs, Tempe, AZ 85284
USA, Res Lab, Aberdeen Proving Ground, MD 21005 USA.
(addresses have been truncated.)
Why do you think your paper is highly
Molecule-to-metal bonds are important in many areas of electronics, and the
paper describes fluctuations in these types of contacts.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
"Our interest was (and still is) in
building molecular photovoltaic devices for
Up to the time of the paper, it was assumed that fluctuations in the
molecule itself caused switching. In the paper we showed that for gold
contacts, fluctuations in the bond itself also matter.
Would you summarize the significance of your paper in
Electrical contacts between a molecule and a gold metal contact will
spontaneously "break" and reform, causing the contact to flicker on and
off. The molecule does not usually leave the surface completely, so the
contact tends to "switch on" again after a while. This places an intrinsic
limit on attempts to make molecular electronic devices with these kinds of
How did you become involved in this research and were
any particular problems encountered along the way?
Our interest was (and still is) in building molecular photovoltaic devices
for energy conversion.
Where do you see your research leading in the
We are now using single-molecule electronic measurements to develop a new
way of sequencing DNA. The switching phenomenon opens a new way to make
measurements of tunneling through DNA base-pairs, though the final real
device will not use gold contacts for obvious reasons!
Do you foresee any social or political implications for
Robust single molecule electronic devices might play a role in lowering the
cost and extending the reach of medical diagnostics.
Edward and Nadine Carson Professor of Physics and Chemistry
Arizona State University
Tempe, AZ, USA
The Biodesign Institute: The Lindsay Lab
Keywords: molecule-to-metal bonds, gold contacts, electrical
contacts, molecular photovoltaic devices, energy conversion,
single-molecule electronic measurements, sequencing DNA, medical